There are many different types of virus according to there infection or according to there fucntionality.

Polymorphic Viruses
There viruses change there behaviour as they infect a system.

Stealth Viruses
They can hide themselves from AV.

Fast and Slow Infectors
They also act in such a way that they can avoid being detected by AV like stealth. ( Dunno much abt such type)

Sparse Infectors
Viruses that don't infect very often.(Dunno abt. them)

Armored Viruses
They infect in such a way that they make disassembly difficult.

Multipartite Viruses
They are the combination of different types of viruses ( I like such type cause they are very harmful)

Cavity (Spacefiller) Viruses
One can figure out what they do by there names.

Tunneling Viruses
Same as stealth.

Camouflage Viruses
They hide themselves from scanners.

NTFS ADS Viruses
Just know the type what they do i dunno cause they are related to NT.

And of the most important is

Virus Droppers
Thses are the programd that are not basically virus they contain a virus and they just drop them in ur system without being notified by the AV cause AV don't treat them as a virus.

U can test ur scanners by the following way:

Write the following line in the text editor and save it by name EICAR.COM. This program that, when run, will display the text EICAR-STANDARD-ANTIVIRUS-TEST-FILE! and, when scanned, should activate your anti-virus program.